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Sunday, December 11, 2011

In class today, we were discussing about causes of acute red painful eyes. I mean red eye as in inflamed eye.

eye anatomy for dummies :P

Eye appears red simply because of dilated blood vessels. Blood vessel are usually very thin and rarely seen in normal people. The big groups on classifying the red eye or sometimes called pink eye is classified into; conjuctivitis (inflammation of conjunctiva) or cyclitis (inflammation of ciliary body).

Conjuctivitis' red eye is much more 'redder' than cyclitis simply because conjuctiva lies most superficial in eye anatomy, whereas ciliary body lies deeper. And simply to differentiate them both, just observe where the vessels come from; from around the iris outward, or the other way around. Of course the latter points to cyclitis....(hurm, enough about this details)

One thing interesting: Doc asks, 'have u seen the eyes of actors in movies? They are very white, clean & clear, right? Is it natural? Noooooo.. they keep putting eye drops to shrink the vessels so it wont be seen, like ours.. but it wont stay long. There is something called 'rebound hyperemia'. At one point, their eye vessel will dilate to the point more than normal people does. You got served!

They were actually talking about the red eye effects when you capture photos with flash. It is called the 'red reflex'. As we all experienced, our eyes will turn red in photos. How annoying.. but after reading the description below, think again!

Red reflex is the reflection of light from outside into the layer beneath retina which is rich in blood supply. To reach this, one's eye need to be clear, and blood vessels should be normal. As the name suggest, red reflex reflects red / orange color from the layer rich in blood (the choroid). This is what happen in normal person.

cutie pie.. anak ust sabli yg comel. (note the red eye effect)

A diseased person may lost this reflex and substituted by another reflex called the 'white reflex'.

This reflex reflects white color when shone light. This happens in conditions like cataracts, retinoblastoma, retinal infection, or retinal detachment. I just want to stress on retinoblastoma because its the most common cause of ocular malignancy in childhood. As other cancer, it is caused by mutated gene. Although not highly fatal, it can cause malfunction of the eye.

Other than red and white reflex, there's also a 'black reflex'.. Scarring and bleeding inside eye can block the transmission of light and reflect no light at all. simply that.